move parameter array initialization to zigplug.Plugin method

Author: bandithedoge

src/clap/root.zig

@@ -168,35 +168,12 @@ fn ClapPlugin(comptime Plugin: type) type {
         fn init(clap_plugin: [*c]const c.clap_plugin) callconv(.c) bool {
             log.debug("init()", .{});
 
-            // TODO: move parameter initialization to a zigplug function
             if (@hasDecl(Plugin, "Parameters")) {
-                const Parameters = Plugin.Parameters;
                 const data = Data.fromClap(clap_plugin);
-                const allocator = data.plugin_data.plugin.allocator;
-
-                const parameters = allocator.create(Parameters) catch {
-                    log.err("Failed to allocate parameters", .{});
-                    return false;
-                };
-                parameters.* = .{};
-                const fields = @typeInfo(Parameters).@"struct".fields;
-
-                var parameters_array = allocator.alloc(*zigplug.Parameter, fields.len) catch {
-                    log.err("Failed to allocate parameters", .{});
+                data.parameters = data.plugin_data.plugin.makeParametersSlice(Plugin) catch {
+                    log.err("failed to allocate parameters", .{});
                     return false;
                 };
-
-                inline for (fields, 0..) |field, i| {
-                    if (field.type != zigplug.Parameter)
-                        @compileError("Parameter '" ++ field.name ++ "' is not of type 'zigplug.Parameter'");
-                    if (field.default_value_ptr == null)
-                        @compileError("Parameter '" ++ field.name ++ "' has no default value");
-
-                    parameters_array[i] = &@field(parameters, field.name);
-                }
-
-                data.parameters = parameters_array;
-                data.plugin_data.plugin.parameters = parameters;
             }
 
             return true;

src/zigplug/zigplug.zig

@@ -87,7 +87,6 @@ pub const Plugin = struct {
     context: *anyopaque,
 
     vtable: struct {
-        // TODO: verify types
         deinit: *const fn (*anyopaque) void,
         process: *const fn (*anyopaque, ProcessBlock, ?*const anyopaque) anyerror!void,
     },
@@ -197,6 +196,30 @@ pub const Plugin = struct {
     pub inline fn process(self: *Plugin, block: ProcessBlock, params: ?*const anyopaque) !void {
         try self.vtable.process(self.context, block, params);
     }
+
+    pub fn makeParametersSlice(self: *Plugin, comptime P: type) ![]*Parameter {
+        if (!@hasDecl(P, "Parameters"))
+            @compileError("'Plugin.makeParametersSlice' was called but plugin has no parameters");
+        const Parameters = P.Parameters;
+
+        const params = try self.allocator.create(Parameters);
+        params.* = .{};
+        const fields = @typeInfo(Parameters).@"struct".fields;
+
+        var parameters_array = try self.allocator.alloc(*Parameter, fields.len);
+
+        inline for (fields, 0..) |field, i| {
+            if (field.type != Parameter)
+                @compileError("Parameter '" ++ field.name ++ "' is not of type 'zigplug.Parameter'");
+            if (field.default_value_ptr == null)
+                @compileError("Parameter '" ++ field.name ++ "' has no default value");
+
+            parameters_array[i] = &@field(params, field.name);
+        }
+
+        self.parameters = params;
+        return parameters_array;
+    }
 };
 
 comptime {